Telemetering receiver



R. G. JEWELL TELEMETERING RECEIVER April 4, 1944.

Original Filed Jan. 17, 1942 2 Sheets-Sheet l Fig.3.

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TELEMETERING RECEIVER Original Filed Jan. 17, 1942 2 Sheets-Sheet 2 Inventor: Richard G. Jewell,

HT yAttoT'neg able zero and full Patented Apr. 4, 1944 TELEMETERING RECEIVER Richard G. Jewell, Swampscott, Mass, assignor to General Electric Compan a corporation of New York Original application January 17, 1942, Serial No.

427,081. Divided and this application April 30, 1943, Serial No. 485,238

5 Claims.

My invention relates to telemetering receivers, and this application is a division of my application Serial No. 427,081, filed January 17. 194.2, wherein is provided with sturdy, compact, and reliable transmitting and receiving Y apparatus, and wherein the transmitter may havecnly one movable brush, and with the system arranged for long scale operation with provisions for adjustscale points. Wh le the claims herein are directed to the receiving apparatus, a description of the complete system is desirable for a satisfactory understanding of the features which determine the receiver scale distribution.

In. the telemeterlng system described in Pat= ent No. 2,248,616, Fans, assigned to the some assignee as the present invention, a transmitter is employed comprising a resistor which may be wound toroidelly or may be wound as s. pair of straight resistors and which is adapted to have a pair of brushes sliding along it energized with direct current, one brush having one polarity and the other brush having the opposite polarity. The receiver consists ci e delta connected ring wound stator with a transversely magnetized cylindrical permonent-mognet rotor. Three conductors are connected between corresponding points in the transmitter resistor and the receiver so that the rotation of the transmitter brushes produces variation in the current distribution in the receiver coils and thereby shifts the angular direction of the magnetic flux passing diametrically across the receiver stator. In this manner the receiver rotor is caused. to reproduce the angular position oi the rotatable member carrying the transmitter brushes, if the transmitter has s toroidal resistor. If the transmitter has 9. straight line resistor, the straight line motion is converted into angular rotation at the receiver. Although one of the brushes may be grounded if all three of the conductors joining the transmitter and the receiver are insulated from ground, it is necessary that the second brush be insulated from ground.

In order to simplify the mechanical problems involved in the construction of the transmitter and in order to facilitate making. the transmitters interchangeable with different types of receivers, with provision for reversing the direction of deflection by interchanging leads at the external connections of either the transmitter or the receiver, I prefer to utilize a transmitter with a single brush and to utilize a construction in which the brush may be grounded so that it may be connected directly to the shaft of a rotatable element the angular position of which is to be indicated or reproduced at a distance. I desire, however, to retain the ability of the system to rotate through a large scale angle and in certain cases to make any desired number of complete 9. telemetering system is disclosed which drawings, and

. unifomiity of scale distribution revolutions. I have found that I may utilize a single grounded brush and still retain the long scale feature by employing a supplementary set of current=distributing resistors. These may be Y-connected to the three conductors joining the transmitter and receiverif a. three-conductor system is employed. It will be understood, however, that my invention is not limited to a three== conductor system and that if a greater number of conductors were employed the supplementary resistors would be increased in number and would be star-connected. Such 2. system of supplementary resistors tends to distort the ileld'oi the receiver and I have found that this field distortion may be reduced by grounding the Y point or neutral of the supplementary resistance V. A further reduction in distortion of scale distribution and torque is obtained by further modifications in the supplementary resistance or in the receiver construction as will he described more in detail hereinafter.

A better understanding of my invention will be afforded by the following detailed description considered in connection with the accompanying those features of the invention which ere believed to be novel and patentable are pointed out in the claims. In. the drawings, Fig. l is an electrical circuit dizlgrem schematically representing one embodiment of my in volition; Figs. 2 and 3 are full circle scales representing two different scale distributions, by way of example, which may be obtained by two different illustrative sets of resistance relationships in the apparatus represented in Fig. i; Fig. 4 is an electrical circuit diagram. schematically representing a certain simplification in the arrangement of Fig. 1; Fig. 5 is a full circle scale illustrating 2. scale distribution which may be obtained in the apparatus of c with one illustretive set of relationships between the resistences; Hg. 6 is an electrical circuit diagram schematically representing a modification in the electrical circuit of Fig. 4-, utilizing a modified form of receiver in order to obtain increased also illustrating e, modified form of transmitter which may be, utilized with any of the system modifications for providing independent zero and full scale adjustment of the scale where the scale is less than 360 degrees but closely approaches it; Fig. '7 is an electrical circuit diagram schematicelly representing a modification in the arrangement of Fig. 8 providing for adjustment of the degree of scale distribution? Figs. 8 and 9 ..re

; a plan view and an elevational View respectively oi the modified form of receiver rotor shown in the apparatus of Fig. '6 which may be utilized in the apparatus of either Fig. 6 or Fig. 7; Figs. 10 and 11 are a plan View and an elevational view respectively of a modified receiver rotor shown and torque, and

in the apparatus .of Fig. 7 which may also be employed in the apparatus of Fig. 6; Fig. 12 is a view of a section cut by a plane passing axially through the receiver in the apparatus of Fig. 6; Fig. 13 is a plan view of the apparatus of Fig. 12; Fig. 14 is a detail view of the coil box for the field structure of the receiver illustrated in Figs. 12 y and 13, and Fig. 15 is a schematic diagram of a modifiecliorm of transmitter for straight line motion. Like reference characters are used throughout the drawings to designate like parts.

The embodiments of my telemetering system illustrated in Figs. 1 and 4 each comprise a transmitter M, a receiver 52, a supplementary set of current-distributing resistances is shown V-connected to a source of electrical energy it which may take the form of a suitable direct current source suchas a battery of cells. The systems illustrated employ three conductors and each of the three principal elements ll, l2 and l3 accordingly has three connection points each corresponding to a connection point of the other two elements. The transmitter it has three terminals it, it and ill corresponding to terminals it, is and 2d of the supplementary resistors it. The receiver it also has three terminals 2!, 22 and 23 corresponding to the terminals previously mentioned.

In the simplified arrangement of Fig. 4 the corresponding terminals are connected together by means of conductors 2d, 25 and 26 extending from the transmitter it to the resistance set it and conductors 2t, 28 and is extending between the receiver i2 and the resistance set 63. In the arrangement of Fig. 1, however, the conductors 2t, 28 and 29 extend from taps 3t, 3t and 32 on the resistor at E3 to the corresponding receiver terminals 2i 22 and 23 respectively.

In the arrangements shown the positive terminal of the current source it is connected to the Y-point 33 of the resistance set it and-the negative terminal of the current source it is connected to the single rotatable brush it of the transmitter M. Theconnection is made by grounding the negative terminal of the current source it and the transmitter brush til to the frame of the machine or ship on which the telemetering system is employed. In this manner v need for an insulated conductor Joining these parts is obviated. If the receiver 82 is to have no grounded neutral, it may be Y or delta connected, and it may take the form illustrated in Fig. 4 of Patent No. 2,248,616, Faus. However, I prefer to connect the receiver coils in star or Y as shown in Figs. 1 and 4 and to connect the neutral point 35 to the negative terminal of the current source M for the sake of providing a more nearly uniform distribution of indications and torque throughout the scale range of the instrument. As illustrated the neutral point 35 is grounded.

The receiver l2 comprises a low hysteresis, relatively permeable stator core 3% linking three receiver coils 37, it, and 39, a transversely magnetized rotatably mounted right-circular cylindrical rotor at composed of high coercive force material such as sintered oxides of iron and cobait as described in the aforesaid Fans patent, a damping ring ill, a pointer t? carried by the rotor so and a scaleltt cooperating with the pointer 42. The scale 63 is shown in fragmentary form in Fig. 1, but it will be understood that it may form a complete circle and that the pointer it? will make any number of complete or fractional revolutions made by the transmitter brush 3%.

This action takes place as a result of the variation of current distribution in the receiver coils 31, 3t and 39 produced by varying the point on the transmitter ii to which the negative or grounded connection is made by the brush 3%. For example, when the brush 3d is at the transmitter terminal 05 the receiver coil 37 is in effect grounded on both sides and current flows equally through the receiver coils 38 and 39. The fluxes produced by the coils 38 and 39 under this condition, act in opposition with respect to the circular circuit through the receiver core 36 and combine to produce a vertical diametrical flux across the core 36 causing the rotor 49 to take up a position with its line of polarization, that is, a line joining the north and south poles, in the vertical position. Rotation of the transmitter brush it changes the current distribution in the various receiver coils and produces a rotation of thereceiver pointer ll corresponding to the rotation of the transmitter brush it. The direction of rotation of the receiver may be reversed by interchanging the connections of any two conductors to the terminals of the transmitter, or the receiver. No internal connections need be disturbed.

However, in the simple system, particularly in the system without the grounded neutral in the receiver it, the scale distribution in the scale points between the transmitter terminals is not reproduced exactly by the receiver pointer.

, Grounding the neutral point of the receiver has the efiect of minimizing the distortion. The

scale distribution illustrated in Fig. 5 may be obtained with the following illustrative values of resistance: R1=125 ohms Ra=l27 ohms R4=250 ohms of each of the resistances from the neutral point 33 to the intermediate terminals 39, 3t and 32 of the supplementary resistance l3, and Re is the resistance value between the aforesaid terminals 3t, 3t and 32 and the end terminals it, 59 and 2e, respectively. The scale distribution of Fig. 2 may be obtained with the following values of resist= ance:

Ri=l25 ohms R2= 30 ohms B4 250 ohms and thescale distribution of Fig. 3 may be obtained with the resistance values My invention is not limited to the use of particular resistance valuespr resistance relationships and it will be understood that the aforeterminals and ground.

said specific values are given merely by way of illustration.

The scale distribution may be varied by varying any one of the resistances R1, R2 or R: with respect to R4. However, I have found that variation of the resistance R: is most eifective. By increasing this resistance value I may open the scale near the points corresponding tothe transmitter taps IE, IS and I1 and accordingly compress the scale between the points corresponding to the transmitter taps. Decreasing this resistance value has the opposite effect. The eflect of the resistance variation is illustrated by the comparison of the scale distributions in Figs. 2 and 3.

Although the telemetering system has been shown with a circular type of transmitter it, it will be understood that the invention is not lim ited to the use of this precise form of transmitter and that a straight line transmitter, for example, may also be utilized such as shown for instance in U. S. Patent No. 22%,741, Sept. 1, i942, Fisk. et al., and copending application Serial lt'o. $24,779, filed July l, 1941, "by R. G. Ballard, both assigned to the same assignee as the present aic= plication.

In Fig. c I have illustrated a telemetering eye tem employing a slightly modified type of mitter ii in which one of the transmitter tench nals it is replaced by a pair of electrically con= nected independently movable taps or I61; and i612 for independently setting the and full scale positions of the pointer when the system is used with a long scale, for example SOD-degree scale indicator. This modified type of transmitter may also be employed with t em= bodiments of Figs. 1 and 4. If the transmitter brush 3% has straight-line motion a straight transmitter it may be used as shown it? i5 with adjustable taps it, ill, its, and this.

Relative freedom from distortion oi either the scale distribution or the receiver tor-cue by the eilect of the resistors it may be obtained out utilizing the special connection of l in cluding resistor Re by a special design of receiver which I have devised. In place or title three-coil receiver shown in Figs. 1 and e, I may employ a. six-coil receiver 52' as shown in Fig. 6, and a rectangular rotor i l. The receiver it has stator coils wound on the core as such as illus= trated in Figs. 1 and s. However. ithas 1r coils 45 to so inclusive. In the arrangement illus trated, which is triple-conductor system, the six-coil receiver is also connected in V. The on posits coils it and it are connected in series between the conductor ill and the grounded neu= tra1 a. The other two pairs of opposite coils are similarly connected in series between the line opposite coils so wound as indicated schematically in r g. l as to cause opposing fluxes in the core 36 with respect to the circular path thereby producing aiding diametrical flux components in the space occu= pied by the rotor. The connection of the neutral point to ground with six coils results some distortion or the magnetic field of the receiver l2, However, this distortion is utilized in coco= junction with modified shape oi the substantially square rotor at, which would in itself tend to have a distorted magnetic field as compared with a transversely magnetized circular cross -section permanent magnet rotor.

Instead of the. rectangular permanent magnet rotor 44 a composite rotor 5! such as illustrated in Fig. 7 may be employed. The rotor 5i is illustrated in greater detail in Figs. 10 and 11, and

like the rotors 44 and may comprise high coercive force magnetic material such as sintered oxide. In the case of the composite rotor there are two relatively short thick sinterecl-oxide parallel bars 52 joined by a non-magnetic block such as the block 52' composed of aluminum which is suitably mounted on pivots, or on a spindle to provide a rotatable mounting for the rotor 5|. Preferably the' comers 53 of either the rotor 44 or the rotor 5| are slightly beveled, as illustrated in Figs. 8 and 10.

I have found that in the case of the circular cross-section transversely magnetized rotor very accurate alignment with the direction of the stator magnetic field is obtained. However, certain inherent errors may exist if distortion in the field is produced by errors arising in a transmitter. I have'i'ound that the six-coil indicator l2 provides suiilcient distortion in the receiver field near the coils to provide the right sort of compensation to correct for the errors in the resistance system comprising the transmitter providing a rotor is used which has the proper'width of pole face to properly utilize this distorted field. Either the rotor to or the rotor ti is suitable for this purpose. The double-bar composite rotor illustrated in Fig. '2 appears to be preferable to the substantially square solid bar rotor li-3 shown in Fig. 6 when the type of resistance system l3 shown in Fig. 4 is utilized in place of the type of resistance system is shown in Fig. 1. However, my invention is not limited to the use of either one type of rotor or the other and, in the case of composite rotors, is not limited to the use ofrotors made up of only two bars as a similar effect may he obtained from a relatively wide solid bar rotor with curved pole races or by the use of a narrow bar rotor with pole shoes Wider than the natural pole face of the magnet. The rectangular rotors of Figs, 6 and 7 give improved results by minimizing errors inherent in the trans mitter when used with two -brush transmitters oi the type disclosed the aforesaid Fans Patent 2,248,616, especially when the rotor is installed in the six-coil field of Figs. 6 and 7.

I have found that a particularly good. scale distribution and torque variation from the standpoint of uniformity be obtained by utilizing a modified connection illustrated in Fig. 7 in which a variable resistor is introduced in the neutral rolmdihg co'nnection of the receiver H2. The degree of correction of scale and torque distortion may be adjusted by varying the value of the resistance or the rheostat Si l.

The receivers illustrated schematically in Figs. 1 to '7 may be constructed in a very compact and sturdy form utilising the construction illustrated. in Figs. 12 and This applies particularly to the siaz coil receiver it. This structural form of receiver comprises a base to which are secured suitable bearings 56 and for the rotoroarrying spindle 553. It will be observed that the bearing or is in the form of a removable adjust= able screw which is bored at one end to receive one end of the spindle 58. The frame is composed of relatively high conductivity material such as brass or aluminum so that it serves also as a damping ring for the rotor. it is shaped to form a cup 55 integral with flanges 6D. The winding structure 63 surrounds the cup portion 59 and rests against the flange portion 60 to which it is secured by a suitable disk 62 fitting over the bearing screw 5'1 and secured against the cup portion 59 of thcjrame by a nut 63 3 threaded on to the screw 61. The three resistors i3 and, ii desired, also the fourth resistor 5% may be mounted on the frame 55 to form a complete unitary structure to be placed at the receiving end of the telemetering system. As illustrated in Fig. 12, the three resistors l3 are wound in pancake form on a spool to with suitable separating insulator disks or flanges 65. An end.

flange as is provided which is notched at a suitable point ti. on the periphery for receiving the connections to the resistors i3 and the spool 6:3 is secured to the disk 62 in any desired manner as by screws 68.

If desired a control magnet or pull-01f magnet of the type and for the purpose described in Patent No. 2,181,803, Faus, is mounted within the spool to. For example, as illustrated in Fig. 13 a control magnet to is transversely mounted in an annular spring ill adapted to fit frictionally within the hub of the spool 6 5 to be angularly as well as axially movable, thereby permitting both adjustment of the strength of the pull-0E torque and adjustment of the angular position of the receiver rotor in case of disconnection of the receiver coils from the power supply or power failure.

For maximum economy in the utilization of ascaess the core, and a rotor mounted within the core in inductive relation to the current conducting coils, said rotor including polarized permanent magnet material for producing a magnetic field diametrispace and material the field structure ca may take the form illustrated in Fig. 14, in which the core has six wedge-shaped split hollow rectangular winding separators ll mounted thereon. The respective coils are machine wound directly on to the core 38 into the spaces between the separators i l.

I have herein shown and particularly described certain embodiments of my invention and certain prising an annular core composed of permeable magnetic material, a plurality of current-conducting coils linking said core and spaced substantially symmetrically around the center of the core, said receiver being of a type in which rotary motion is reproduced in response to relative variations in the energization of the several coils about set forth in claim 1 in which the rotor comprises a pair of high coercive force bar magnets mounted parallel and spaced apart on a non-magnetic rotatable member in a plane perpendicular to the axis of rotation.

3. A receiver for a telemetering system comprising a frame composed of electrically conducting material having a cup portion and a flange portion adjacent the cup portion substantially coaxial therewith, a rotor rotatably mounted within said cupportion which cup portion serves as a damping cup for the rotor, a magnetic field producing unit mounted against said flange portion of the frame and around the cup portion and comprising an annular core of relatively permeable magnetic material wound with a plurality of current-conducting coils, a plurality of resistors wound in pancake form and laid together fiatwise against said field producing unit substantially coaxial therewith and connections interconnecting said field coils and said resistors with a star connection.

a 4. A receiver for a telemetering system, said receiver being of the rotatable permanent magnet type, a spool mounted against said receiver flatwise substantially coaxial therewith, said spool containing a plurality of current distributing resistors interconnected with the receiver and having a hub portion, a member adjustable in position within said spool hub portion and a permanent magnet secured to said last-mentioned member in transverse'position with respect to said spool hub and the axis of the instrument for providing an adjustable pull-ofi field adapted to react with the rotor of the receiver.

5. A receiver for a telemetering system such as set forth in claim 1 in which the rotor consists of a permanent magnet having a substantially square cross section perpendicular to the axis of rotation and centered with respect to said axis.

RICHARD G. JEWELL. 

